Diesel fuels are chemical mixtures with temperature-dependent properties. One property of particular concern relates to the formation of solid particulate matter at cool operating temperatures. For example, cold temperatures may induce solids dissolved in the fuel to become insoluble, which precipitously causes a cloudy appearance in the fluid fuel. The fuel cloud point refers to the temperature at which dissolved solids are no longer completely soluble in the fuel mixture. Thus, cooling temperatures near the cloud point may cause a second phase to form in the fuel that can lead to the development of engine problems. The solids formed may be wax crystals that are commonly referred to as fuel gels. In this way, fuel gelling may occur when the temperature falls to a point where wax crystals start to form in the fuel. Precipitous accumulation in the fuel may cause problems by plugging the fuel filter, fuel line, injector and/or the fuel system in general, which causes engine damage that prevents the engine from starting or running.
Previous methods and systems for detecting wax formation in a diesel fuel tank are based on determining one or more temperatures in the fuel tank via the placement of dedicated sensors therein. For example, WO2012169957 discloses a method of determining waxing of the fuel in the fuel tank using a first temperature sensor to find the temperature at a first region in a fuel tank and a second sensor to determine the temperature at a second region in the fuel tank. Then, the difference between both sensor temperatures is compared to a limiting value to determine if waxing of fuel in tank has occurred. Alternatively, JP2013068195 describes an abnormality detection apparatus of a fuel filter using a method that determines fuel filter clogging via pressure sensors provided before the inlet and after the outlet of the fuel filter. Then, in response to fuel gelling, a pressure difference develops that is used to indicate further actions for preventing fuel clogging.
The inventors have recognized issues with such approaches and herein describe a fuel gelling determination method based on ambient conditions in the vicinity of a vehicle. The approaches described further include displaying a driver notification specifying a potential need for fuel additives due to fuel gelling responsive to past ambient temperatures and current ambient temperatures. In one particular example referred to as the first embodiment, the method comprises measuring and storing one or more ambient air temperatures on-board the vehicle at a pre-determined interval, such as at each mile. Then, at a fuel refill event the method includes calculating an average ambient temperature based on at least a portion of the stored ambient air temperatures, wherein the determination of the temperature allows for characterizing a fuel grade based on a comparison of the calculated average ambient temperature to a first reference temperature selected to indicate that favorable fuel gel forming conditions exist. As described in greater detail below, the fuel grade may be characterized as a summer grade of fuel that is susceptible to gel formation when the calculated average ambient air temperature exceeds the first reference temperature whereas the fuel is characterized as a winter fuel grade when the average temperature falls below the threshold. In this way, the fuel gelling determination method uses the ambient conditions detected near the vehicle to determine a potential for fuel gel formation within the fuel system, and notifies a vehicle operator of the conditions via a message sent to a display. The technical result can be achieved since fuel gel formation can be prevented by addition of a diesel additive into the fuel. A second embodiment further describes a fuel gelling determination method for use during vehicle operation.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings. It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.